Parallel.ForEach 添加到列表 [英] Parallel.ForEach with adding to list

问题描述

我正在尝试运行多个连接到远程站点(通过网络)并返回通用列表的函数.但我想同时运行它们.

I'm trying to run multiple functions that connect to a remote site (by network) and return a generic list. But I want to run them simultaneously.

例如:

public static List<SearchResult> Search(string title)
{
    //Initialize a new temp list to hold all search results
    List<SearchResult> results = new List<SearchResult>();

    //Loop all providers simultaneously
    Parallel.ForEach(Providers, currentProvider =>
    {
        List<SearchResult> tmpResults = currentProvider.SearchTitle((title));

        //Add results from current provider
        results.AddRange(tmpResults);
    });

    //Return all combined results
    return results;
}

在我看来，对结果"的多次插入可能同时发生......这可能会导致我的应用程序崩溃.

As I see it, multiple insertions to 'results' may happend at the same time... Which may crash my application.

我怎样才能避免这种情况?

How can I avoid this?

推荐答案

//In the class scope:
Object lockMe = new Object();    

//In the function
lock (lockMe)
{    
     results.AddRange(tmpResults);
}

基本上一个锁意味着只有一个线程可以同时访问那个临界区.

Basically a lock means that only one thread can have access to that critical section at the same time.

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